Direct Printing of Micropatterned Plasmonic Au Nanoparticle/MoS 2 Heterostructure for Ultrasensitive Surface‐Enhanced Raman Spectroscopy Sensing

Abstract Molybdenum disulfide (MoS 2 ) has attracted a wide range of research attention due to its distinct electronic structures and the great potential for use in emerging microelectronic and photonic devices. However, the development of MoS 2 ‐based micro‐electronic/photonic devices lags far behind expectations mainly because of the lack of efficient microfabrication technology. Here, a high‐resolution precision photoreduction technology is presented for directly printing MoS 2 micropatterns that can be decorated into gold nanoparticle (AuNP)/ MoS 2 heterostructure for ultrasensitive surface‐enhanced Raman spectroscopy (SERS) sensing. Micropatterns of MoS x nanoparticles are initially grown toward a target size in a light‐controlled manner and then transformed into a micropatterned pure MoS 2 nanofilm through thermal annealing. Thereafter, size and gap‐controlled AuNPs are grown selectively on the surface of MoS 2 to form a self‐aligned AuNP/MoS 2 heterostructure with desired optical properties. Thanks to both electromagnetic and chemical enhancements, the directly printed plasmonic AuNP/ MoS 2 substrate can greatly enhance Raman signals to detect crystal violet (CV) and 4‐mercaptobenzoic acid (4‐MBA) at 10 −12 m under the excitation of 785‐nm laser. This multiscale‐engineered plasmonic AuNP/MoS 2 substrate is rapidly printed without relying on expensive and time‐consuming nanofabrication processes, offering a new technical approach for future development of MoS 2 ‐based micro‐devices and sensing platforms.